mediaview: Fix ARC file system operation deferring.

chrome/browser/chromeos/arc/fileapi/arc_file_system_operation_runner_util.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/arc/fileapi/arc_file_system_operation_runner_util.h"
 
 #include <utility>
 #include <vector>
 
 #include "chrome/browser/chromeos/arc/fileapi/arc_file_system_operation_runner.h"
@@ skipping 16 matching lines @@
       BrowserThread::IO, FROM_HERE,
       base::Bind(callback, base::Passed(std::move(result))));
 }
 
 void GetFileSizeOnUIThread(const GURL& url,
                            const GetFileSizeCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   auto* runner =
       ArcServiceManager::GetGlobalService<ArcFileSystemOperationRunner>();
   if (!runner) {
+    LOG(ERROR) << "ArcFileSystemOperationRunner unavailable. "
+               << "File system operations are dropped.";
     callback.Run(-1);

[hidehiko, 2017/02/23 08:36:04]

(Not due to this change but) Looks a bug (missing return)?
If you'd like, I'm ok to leave this as is in this CL, and to address it in
another CL.

[Shuhei Takahashi, 2017/02/23 08:49:30]

Great catch! Let's fix it now.

   }
   runner->GetFileSize(url, callback);
 }
 
 void OpenFileToReadOnUIThread(const GURL& url,
                               const OpenFileToReadCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   auto* runner =
       ArcServiceManager::GetGlobalService<ArcFileSystemOperationRunner>();
   if (!runner) {
+    LOG(ERROR) << "ArcFileSystemOperationRunner unavailable. "
+               << "File system operations are dropped.";
     callback.Run(mojo::ScopedHandle());
     return;
   }
   runner->OpenFileToRead(url, callback);
 }
 
 void GetDocumentOnUIThread(const std::string& authority,
                            const std::string& document_id,
                            const GetDocumentCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   auto* runner =
       ArcServiceManager::GetGlobalService<ArcFileSystemOperationRunner>();
   if (!runner) {
+    LOG(ERROR) << "ArcFileSystemOperationRunner unavailable. "
+               << "File system operations are dropped.";
     callback.Run(mojom::DocumentPtr());
     return;
   }
   runner->GetDocument(authority, document_id, callback);
 }
 
 void GetChildDocumentsOnUIThread(const std::string& authority,
                                  const std::string& parent_document_id,
                                  const GetChildDocumentsCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   auto* runner =
       ArcServiceManager::GetGlobalService<ArcFileSystemOperationRunner>();
   if (!runner) {
+    LOG(ERROR) << "ArcFileSystemOperationRunner unavailable. "
+               << "File system operations are dropped.";
     callback.Run(base::nullopt);
     return;
   }
   runner->GetChildDocuments(authority, parent_document_id, callback);
 }
 
 }  // namespace
 
 void GetFileSizeOnIOThread(const GURL& url,
                            const GetFileSizeCallback& callback) {
@@ skipping 32 matching lines @@
       base::Bind(
           &GetChildDocumentsOnUIThread, authority, parent_document_id,
           base::Bind(
               &PostToIOThread<base::Optional<std::vector<mojom::DocumentPtr>>>,
               callback)));
 }
 
 }  // namespace file_system_operation_runner_util
 
 }  // namespace arc